This project will examine proteolytic mechanisms involved in whole blood fibrinolysis. Interactions between the humoral and cellular elements involved in fibrin clot lysis will be defined, as will the effect of vascular injury with endothelial disruption. Although initial efforts will focus on the relative contributions of plasma and cellular enzymes to fibrinolysis, the goal of the program is to extend these observations to the role of protease function in the body's network of defenses against injury.